鄂尔多斯盆地大牛地奥陶系马五_2段储层成岩相

Reservoir Diagenetic Facies of Ma5_2 Submember in Ordovician in Daniudi Area,Ordos Basin,Western China

通过岩心、薄片观察,结合测井、地球化学数据分析,认为大牛地马五2段主要有利储层发育的成岩作用为溶蚀作用、白云石化作用和破裂作用。综合分析得出马五2段储层成岩相主要包括泥质充填成岩相、去云化成岩相、去膏化成岩相以及白云石化成岩相,对马五2段成岩相的展布进行了深入分析,发现泥质充填成岩相主要沿岩溶沟槽的边缘分布,说明泥质充填相可能受古地貌的控制;去云化和去膏化成岩相主要在较高的部位发育;白云石化成岩相主要受沉积相分布的控制。对马五2段储集空间进行测井识别后认为,成岩相反映了沉积微相所决定的溶蚀差异特征;成岩相的分布反映了古地貌对岩溶储层的控制作用;白云石化成岩相为较为有利的储集相带分布区。

According to the observation on core and thin section, and the analysis of well logging, the dia- genesis of reservoir development of Ma52 Submember in Daniudi area include dissolution, dolomitization and fracture. The reservoir diagenetic facies.of Ma52 Submember mainly include the argillaceous filling dia- genetic facies, dedolomitization diagenetic facies, degypsification diagenetic facies, and dolomitization dia- genetic facies. Further analysis on the Ma52 distribution of diagenetic facies reveals that argillaceous filling diagenetic facies mainly located along the marginal distribution of karst groove and controlled by geomor- phology. Dedolomitization diagenetic facies and degypsification diagenetic facies are mainly developed in the highland while dolomitization diagenetic facies is mainly controlled by sedimentary facies distribution. This paper concludes that. The sedimentary microfacies reflected by diagenetic facies determine the dis- solution differences; The distribution of diagenetic facies illustrates the controling impact of palaeogeo- morphology on karst reservoir; Dolomitization diagenetic facies are relatively favorable distribution area for reservoir facies.